Rack and clamp for enlargers



June 7, 1938. w. H. HOLDER BACK AND CLAMP FOR ENLARGERS Filed March 28, 1956 65 post I), the upper end of which is provided with meat.

Patented June 1, 1938 2,119,710

UNITED STATES PATENT OFFlCE RACK AND CLAIWP FOR ENLARGERS William H. Holder, Rochester, N. Y., assignor, by

mesne assignments, to Eastman Kodak Company, Jersey City, N. J., a. corporation of New Jersey Application March 28, 1936, Serial No. 71,469

9 Claims. (Cl. 88-24) The present invention relates to photography a caplike number I having outwardly and upand more particularly to photographic enlarging wardly extending arms IS on which is rotatably cameras, which have a focusing lens movable mounted a pulley IS, the purpose of which conrelative to a negative holding frame and to a struction will be hereinafter more fully described.

sensitized-paper easel to enable a wide range of Slidably mounted on the post I3, is a bracket 5 enlargements or reductions to be made. One ob- 20 formed with spaced laterally extending arms. ject of the invention is to provide an improved 2| adapted to engage the camera frame 22 to rack and clamp for enlarging cameras. Another support the latter, in the usual and well known object is to provide a rack and clamp which will manner. Secured to the bracket 20 and dependenable the lens to be easily and quickly adjusted ing therefrom is a plate 23 having tracks, pref- 10 and, when adjusted, to be securely held against erably in the form of racks, 24 arranged on the accidental movement until it is again reposifront face thereof. The lower end of the plate tioned. Another object is,to provide a rack and 23 is fastened, in any suitable manner, to thearms clamp of the type described which is simple in 25 of a lower bracket 26 also slidably mounted construction, relatively inexpensive to manufacon the post 13. The brackets and 26 thus pro- 15 ture, and effective in use. Still another object is vide a two-bearing support for the camera, and to provide a rack and clamp of the class described are arranged to slide vertically on the post l3 to which is automatically adjusted for wear of the properly position the camera relative to the paper retaining parts and thus assures that the lens will easel l I.

20 be held in-proper adjusted position irrespective The enlarging camera is of the usual construc- 20 of the wear of the device. A further object is to tion and comprises, in general, a negative holdprovide a mechanism for adjusting the apparatus ing frame 30, and a lens 32 mounted on a suitable by means of two coaxially arranged knobs mountlens board 33 and connected to the holding frame ed on a single shaft, one knob rotatably mounted 30 by means of a depending bellows 34 which en- 2 to afford rapid adjustment of the shaft, and the ables the lens to be moved relative to the holding other knob affixed to the shaft for fine adjustframe for the purpose of focusing, as is well ments thereof. known to those familiar with the art. The frame To these and other ends, the invention conis arranged to receive a negative holder 35 on sists in certain improvements and combinations which is placed a negative (not shown),the image 30 of parts all as will be hereinafter more fully exof which is projected, by means of a suitable light, 30 plained, the novel features being pointed out in through the lens 32 and onto the sensitized paper the claims at the end of the specification. position on the easel I l. A reflector 31 is detach- In the drawing: ably mounted on the holding frame 30 and car- Flg. l is a side elevation of an enlarging camera ries a light source, preferably in the form of an 35 in diagrammatic form, including an adjustment electric lamp 38, which is connected to a suitable 35 mechanism constructed in accordance with a presource of electric current (not shown). ferred embodiment of my invention; In order to make different sizes of enlargement Fig. 2 is a sectional horizontal view taken suband reductions, it is often necessary to adjust the stantially on the line 2-2 of Fig. 1, showing the entire camera relative to the easel' II, as is well 40 adjustment mechanism with the clutch in enknown. To this end, the bracket 20 is formed 40 gaged position to securely retain the lens in adwith a projecting ear 40 to which is secured a justed position; and cable I arranged to run over the pulley l6 and Fig. 3 is a horizontal sectional view of a porthrough an opening in the cap it and into the tion of the mechanism shown in Fig. 2 and shows interior of the post I 3. A suitable counterweight 5 the clutch in the disengaged position to permit 42 is fastened to the free end of the cable ll 45 free movement of the lens. within the post l3. When the camera is to be Similar reference numerals throughout the sevadjusted relative to the easel II, the brackets 20 eral views indicate the same parts. and 26, with their connecting plate 23, are slid Referring now to the drawing, ll indicates a longitudinally along the post I! until the desired supporting base or easel onwhich the sensitized position is reached. The cable 4| running over 50 paper is positioned to receive a projected image. the pulley It, raises or lowers the counterweight This ea l base is formed, at one ,end thereof, 42 within the post l3. After the-camera has been with an upwardly extending hub 12 adapted to properly positioned relative to the easel i l, the receive a vertically extending hollow supporting counterweightwill then maintain this adjust- In addition to moving the entire camera relative to the easel l i, it is also essential to properly focus the lens relative to the negative holder To accomplish this result, the present invention provides an improved rack and clamp which will positively yet resiliently retain the lens inadjusted position, but which may be readily releasedv to permit the easy and rapid adjustments of the lens new position.

The preferred embodiment of the rack and clamp is clearly illustrated in section in Fig. 2, and comprises two-spaced members generally indicated by the numerals l5 CG. Each of these members has one end thereof formed to provide a vertically extending portion if, of any suitable shape, having a slot arranged to slidably engage a vertical edge of the plate a horizontal extending lens supporting arm to which the lens board is secured in any suitable manner; and an inwardly extending boss fill inmrinediate the ends, all of which is clearly illustrated in Fig. 2. The bosses or hubs 5t provide spaced bearings for a shaft on which are slidably and rotatably mounted wheels, preferably in the form of pinions Ell, which engage or mesh with the rack so that when the shaft is rotated the pinions will roll along the rack to move the lens board.

Each of the pinions 5? is provided with an axially extending reduced shoulder a face of which engages a cooperating and adjacent face of the hub or bearing 5b to limit the movement of the pinion M in one direction. The pinions are held in spaced relation by means of a spacing tube which fits loosely on the shaft 55 and engages the opposite or inner faces M of the pinions. The spacing tube thus cooperates with the shaft bearings 5b to maintain the pinions 5i in alignment with the rack 26;, as clearly illustrated in Fig. 2.

The pinions El are preferably splined on the shaft 55 so that they will be rotated when the shaft rotates, but will permit axial movement of the shaft relative thereto. To secure this result, each of the pinions 5i is preferably formed with an open end slot ill arranged to receive an upwardly extending pin El secured to and rotatable with the shaft 55. When the lens 32 is to be shifted to a new position relative to the holding frame so, the shaft 55 is moved to the right, as viewed in Fig. 2, to disengage a clutch, indicated generally by the number l5 and hereinafter more fully described. When the shaft is thus slid axially, the pins ll move longitudinally in the slots l9. Upon rotation of the shaft 55, however, the pins H engage the sides of the slots 10 and rotate the pinions as a unit with the shaft, to properly adjust the lens. When the lens is thus adjusted, the shaft is then slid axially to the left, as viewed in Fig. 2, to re-engage the clutch to frictionally retain the lens in adjusted position.

The clutch 15 comprises, in the present embodiment, a disk like member 16 secured to an extension of the shaft 55 by means of a pin 18, and a friction portion preferably in the form of a cork ring mounted on the arm 49 of the member 48, as shown in Figs. 2 and 3. The disk 16, in the present embodiment, is formed with a conical friction face or surface 8| arranged to engage a similarly shaped face 82 on the ring 89 to frictionally hold the shaft 55 against rotation, or to move out of engagement with the face 82, as shown in Fig. 3, to permit the free rotation of .the shaft 55 to position the lens. Fine adjustmerits of the lens may be secured by slightly rotating the shaft 55, with the clutch in engagement as shown in Fig. 2, so as to slide the face El of the disk "l6 on the face 92 of the friction ring fill.

It is desirable to properly position the face ill of the disk l6 relative to the face [if of the ring llll. To this end, the ring dll is provided with two or more holes lflf. in which the retaining screws Hi3 loosely fit. These screws extend through the ring fill and into registering threaded holes lll l in the arm A suitable washer ldil, preferably metallic, is placed under the heads of the screws 8% to provide a suitable bearing therefor. The holes hi2 are preferably made slightly larger than the screws ill? so that the ring Ell may be adjusted slightly to properly align the engaging faces ill and 82 of the clutch members. After the ring has been thus adjusted, the screws MS may be screwed down by a suitable screw- 4 driver which may be brought into engagement with the screws through the apertures Mill in the ring "it, which apertures are in registry with the screws hi3 and the holes M12, as is clearly illustrated in Figs. 2 and 3.

The shaft 55 may be rotated or moved axially in the manner above described by any suitable means, but preferably by a dish-shaped hand knob 85 secured to an extension 86 of the shaft by means of a pin t'l, so that the knob 65 will rotate with the shaft. When the shaft 55 is to be rotated a substantial amount, the knob I 5 is pressed in, or to the right as viewed in Fig. 2, to disengage the clutch; but when only a slight adjustment is desired, the knob 85 is rotated to rotate the shaft and slide the engaging surfaces of the clutch as pointed out above. A spiral spring illl surrounds the extenison 86 of the shaft 55, and has one end thereof in engagement with the face M of the member 45 and the other end in engagement with a shoulder 92 of the knob 85. This spring thus tends to force the knob 85, shaft 55 and disk Hi to the left, as viewed in Fig. 2, to bring the clutch surfaces into engagement. The spring thus cooperates with the friction clutch to provide means for frictionally retaining the lens in adjusted position. It is apparent that as the faces 8| and 82 of the clutch tend to wear, the spring 90 will move the shaft 55 and the disk 16 to the left, as viewed in Fig. 2, and thus automatically compensate for the wear in the clutch parts.

The present invention also preferably provides an auxiliary dish-shaped palm knob 95 which cooperates with the hand knob 85 to shift the shaft 55 to disengage the clutch. This palm knob 95 is, by preference, slightly smaller than the hand knob 85 and isconcentrically positioned in the dished or hollow portion 96 thereof, and has a rim portion 91 which projects slightly beyond the concentric rim 98 of the hand knob 85. The palm knob 95 is formed with an inwardly extending tubular sleeve I00 arranged to rotate freely on the shaft 55, so that when the shaft rotates the palm knob will remain stationary against the palm of the hand. The palm knob 95 is rotatably secured to the shaft 55 by the head ml of a stud which extends through the center of the palm knob and engages a threaded opening in the end of the shaft, as clearly illustrated in Fig. 2. This construction enables the palm knob to cooperate with the hand knob in moving the shaft axially; but when the shaft is rotated, the palm knob remains stationary against the palm of the hand, the advantages of which constructions are obvious.

The operation of the device is as follows. When a slight adjustment of the lens is desired, the hand knob is rotated in the proper direction, thus rotating the shaft 55 which carries with it the clutch disk 16. When the disk 16 is thus rotated, the friction face 8| thereof slides over the registering face 82 of the'friction ring 80 until the proper adjustment is secured, after which the clutch members are resiliently held in frictional engagement by means of the spring to retain the lens in adjusted position. When, however, a large movement of the lens is desired, the palm knob 85 is pressed inwardly and cooperates with the hand knob 85 to move the shaft 55 axially to disengage the clutch members 16 and 80. When the clutch members are thus disengaged, the lens may be easily and quickly ad- Li justed by moving or rolling the pinions 51 along the rack 24. For example, if the adjustment is to be downward, it is only necessary to press the palm knob with the palm of the hand, and when the clutch is disengaged, the lens will rapidly move downward under its own weight, the palm knob remaining stationary against the palm of the hand. For the sake of lightness, the hand and palm knobs may be made of wood, bakelite or any other suitable light material. If desired, the clutch may be suitably enclosed.

While this rack and clamp has been shown in connection with enlarging cameras, this is by way of illustration only, as it is contemplated that this mechanism is adapted to a wide variety of uses. The applicant, therefore, intends to cover all modifications which come within the spirit of the invention and the scope of the appended claims.

What I claim is:

1. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a shaft mounted for rotation on said member, a wheel secured to said shaft and arranged to engage said track to move said member relative thereto, a friction portion associated with said member, means including a disk mounted on said shaft and having a part thereof arranged to engage said portion to retain said movable memher in adjusted position, means secured to said shaft and rotatable therewith to rotate said disk onsaid portion for slight adjustments of said movable member, and means rotatably mounted on said shaft and arranged to move said shaft axially to disengage said disk from said portion to permit large adjustments of said movable member.

2. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a shaft mounted for rotation on said member, a wheel secured to said shaft and arranged to engage said track to move said member relative thereto, a friction clutch cooperating with said movable member to frictionally retain the latter in adjusted position, a focusing hand knob secured to said shaft and rotatable therewith to rotate said clutch against the frictional resistance thereof for slight adjustments of said movable member, a focusing palm knob rotatably mounted on said shaft adjacent said hand knob and arranged to move said shaft to disengage said clutch to permit said wheel to move rapidly along said track for large adjustments of said movable member, and resilient means associated with one of said knobs and tending to move the latter axially to engage said clutch.

3. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a wheel mounted on and rotatable with said shaft and arranged to engage said track to adjust said movable member, retaining means cooperating with said movable member to retain said wheel in alignment with said track so as to move therealong, friction clutch means associated with said shaft to hold the latter against rotation to maintain the movable member in adjusted position, said shaft being movable axially to permit disengagement of said clutch means, focusing means mounted on said shaft and arranged to both rotate said shaft against the friction of said clutch to provide slight adjustments to said movable member and to move said shaft axially to disengage said clutch to afford large and rapid adjustments of said movable member.

4. In a photographic enlarging camera, the combination with a supporting frame having spaced tracks thereon, of a movable member slidably mounted on said support and arranged to carry a lens board movable bodily therewith, a shaft mounted for rotation on said movable member, spaced wheels on said shaft arranged to engage said track to move said member relative thereto, each of said wheels having an axially extending slot formed therein, a pin on said shaft arranged to extend into said slot, said pin being movaole in said slot when said shaft is moved axially but engaging an edge of said slot when said shaft is rotated to rotate said wheel, retaining means cooperating with said movable member to retain said Wheels in alignment with said tracks, friction clutch means mounted on said shaft adjacent one end thereof and having a part thereof arranged to frictionally engage a cooperating friction portion secured to said movable member to frictionally hold the latter in adjusted position,

a hand knob secured to the shaft adjacent the other end thereof and arranged to turn said clutch means against the frictional resistance of said portion to afford slight adjustments of said lens board, said hand knob being spaced from said movable member, a palm knob rotatably mounted on said shaft adjacent said hand knob and arranged to move said shaft axially, said palm knob being adapted to cooperate with said hand knob to disengage said clutch means to permit said wheels to move along said track to adjust said lens board, and a resilient member having a part thereof engaging said hand knob and tending to move said shaft axially to bring said clutch means into engagement with said portion.

5. In a photographic enlarging camera, the combination with a supporting frame having spaced tracks thereon, of a movable member slidably mounted on said support and arranged to carry a lens board movable bodily therewith, a shaft mounted for rotation on said movable member, spaced wheels on said shaft arranged to engage said track to move said member relative thereto, each of said Wheels having an axially extending slot formed therein, a pin on said shaft arranged to extend into said slot, said pin being movable longitudinally in said slot when said shaft is moved axially but engaging an edge of said slot when said shaft is rotated to rotate said wheel, retaining means cooperating with said movable member to retain said wheels in align- 'ment with said tracks, a friction portion on said movable member adjacent one end of said shaft,

a clutch disk secured to said shaft adjacent said one end and having a face thereof arranged to engage a complementary face of said portion to frictionally retain the movable member in adjusted position, a hand knob secured to the shaft adjacent the other end thereof and arranged to both turn said disk on said portion to provide slight adjustments of said lens board or to move said shaft axially to disengage said disk from said portion to permit said movable member to be moved freely along said track, a palm knob rotatably mounted on said shaft adjacent said hand knob and arranged to move said shaft axially to disengage said disk from said portion, and resilient means engaging said hand knob and tending to move said shaft axially to bring said disk into engagement with said portion to frictionally secure the lens board in adjusted position.

6. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a shaft rotatably and slidably mounted on said member, a wheel secured to said shaft and arranged to engage said track to move said member relative thereto, a friction clutch associated with said. shaft, said shaft being slidable to disengage said clutch to permit large and rapid adjustment of said movable member and slidab-le in the opposite direction to engage said clutch to maintain said movable member in adjusted position, means including a member loosely mounted on said shaft for sliding the latter, and means for turning said engaged clutch slightly to permit, small adjustments of said movable member.

7. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a shaft rotatably and slidably mounted on said member, a wheel slidable mounted on but,

rotatably secured to said shaft and arranged to continuously engage said track to move said member relative thereto, a clutch associated with said shaft, said shaft being slidable in one di rection to disengage said clutch to permit large and rapid adjustments of said movable member and slidable-in another direction to engage said clutch to maintain said movable member in adjusted position, and means for both rotating said shaft to turn said'engaged clutch slightly to permit small adjustments of said movable member and to slide said shaft axially to disengage said clutch to permit large adjustments of said movable member.

8. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a shaft rotatably and slidably mounted on saidv member, a friction portion associated with said member, a disk on said shaft positioned to engage said portion to frictionally retain said movable member in adjusted position, focusing means secured to said shaft to rotate said disk on said portion for slight adjustments of said movable member, and means independent of but cooperating with said focusing means for moving said shaft axially to disengage said disk from said portion to permit large and rapid adjustments of said movable member.

9. In a photographic enlarging camera, the combination with a supporting member having a track, of a member movable relative to said track, a shaft rotatably and slidably mounted on said member, a friction portion associated with said member, a disk on said shaft positioned to engage said portion to frictionally retain said movable member in adjusted position, means secured to said shaft to rotate said disk on said portion for slight adjustments of said movable member, means rotatably mounted on said shaft for moving the latter axially in one direction to disengage said disk from said portion to permit large adjustments of said movable member, and resilient means engaging said first mentioned means to move said shaft axially in the opposite direction to bring said disk into engagement with said portion to retain said movable member in adjusted position. I

WILLIAM H. HOLDER. 

